Known in the art is a porous heat-insulation material comprising blocks moulded from granules of a foamed synthetic resin with a cement coating bonded with each other by means of a cement-like binder (cf. U.S. Pat. No. 3,104,196 Cl. 161-168, 1963).
This prior art porous heat-insulation material has a high volume mass (320 to 350 kg/m.sup.3), low porosity and, consequently, an increased thermal conductivity. Furthermore, this material contains a large amount of the binder (ratio between masses of the synthetic resin and cement-like binder is equal to 1:0.4 to 1.6). This material also features a low plasticity.
Known in the art is a porous heat-insulation material comprising blocks moulded from granules of expanded perlite sand with a thermoplastic (asphalt resin) coating bonded together by means of a hydrophobic binder, i.e. pitch (cf. U.S. Pat. No. 3,655,564 Cl. 252-378, 1972).
This prior art material has disadvantages reading in its creep at elevated temperatures (70.degree. to 100.degree. C.), a high content of the binder (up to 60% by mass). Volume mass of said material is 300 kg/m.sup.3 and above. Furthermore, this material is combustible.
Also known in the art is a heat-insulation material comprising blocks moulded from granules of foamed mineral filler (e.g. clay, glass) with a thermosetting polymeric coating (epoxy, phenol-formaldehyde, unsaturated polyester resins); voids between granules are at least partly filled with a foamed synthetic resin (cf. U.S. Pat. No. 3,551,274 C. 161-168, 1970).
This material, however, consists of large-size granules only (1.5 to 1.8 mm), therefore the possibility of using finely-divided mineral fillers is restricted. Said thermosetting coating is non-uniformly distributed over the surface of granules. The material has a low plasticity value. The content of said thermosetting polymer in the material is rather high, i.e. about 30% by mass. Volume mass of the material is also high (180-240 kg/m.sup.3).